The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
FIG. 1 illustrates the gear-shift mechanism of a typical automated manual transmission to which the present disclosure can be applied, and shows in detail a double-clutch transmission.
Referring to FIG. 1, two fingers F, which are vertically moved to perform a selecting operation and are rotated to perform a shifting operation, are provided. An odd-numbered stage selecting actuator 9 and an even-numbered stage selecting actuator 13, which vertically move the two fingers F, respectively, and an odd-numbered stage shifting actuator 11 and an even-numbered stage shifting actuator 15, which rotate the two fingers F, respectively, are provided. As shown in FIG. 2, the two fingers F are configured to perform a selecting operation by vertically moving in respective gear-shift gate patterns and perform a shifting operation by horizontally moving in the patterns, thus performing a desired gear-shift operation.
Here, the odd-numbered stage selecting actuator 9 and the even-numbered stage selecting actuator 13 are implemented as a solenoid actuator, and the odd-numbered stage shifting actuator 11 and the even-numbered stage shifting actuator 15 are implemented as a motor. To recognize the positions of the fingers F based on the operation of the motor due to the characteristics of the motor, a separate position sensor is required. However, the position sensor is disadvantageous in that it increases the production cost of products and is additionally unfavorable in the configuration of packages and the weight of products.
In order to recognize the positions of the fingers, during the startup of a vehicle, the fingers are located at specific reference positions. If it is checked that the fingers are located at the specific reference positions, the subsequent rotation of the motor is calculated based on the reference positions, thus tracking and recognizing the positions of the fingers.
For reference, in FIG. 2, the reference positions of the two fingers F are indicated. However, since it cannot be guaranteed that the fingers F are located at the reference positions, such as those shown in the drawing, during the startup of the vehicle, an initialization operation of moving the fingers F to the reference positions must be performed.
FIG. 3 illustrates a conventional method of setting the reference position of a finger, that is, an actuator. In the drawing, during ignition-on of a vehicle, a finger F is moved to both ends in a shifting direction in the sequence of numbers, as shown in FIG. 3, and thereafter the full stroke of the finger F is checked. When the full stroke satisfies a preset value, the finger F reaches a position where selecting is enabled if the finger moves to the position that is half of the full stroke. Therefore, it is possible to check and set the accurate reference position of the finger F by moving the finger F to the position where selecting is enabled and by then reciprocating the finger F in a selecting direction.
However, the above-described initialization procedure is problematic in that noise and a time delay are caused due to gear engagement because the finger F is fully moved in the shifting direction.